1. Field of the Invention
The present invention relates to connectors for connecting an apparatus and a cable, and particularly to connectors used under the conditions of vibration, such as in vehicles.
2. Description of Related Art
In vehicles and other applications, connectors are commonly used for connecting an apparatus (such as a power converter) and a cable. FIGS. 4 and 5 illustrate a conventional connector structure. As shown, the connector includes: a male connector to be connected to an electric apparatus; and a female connector to be connected to a cable 16. FIGS. 4 and 5 illustrate how the male and female connectors are connected to each other. The male connector includes an outer housing 1, an inner housing 2, and a male terminal 3. The female connector includes an outer housing 4, an inner housing 5, and a female terminal 6. The outer housing 4 of the female connector is made of aluminum and has an opening through which the cable 16 is inserted.
As shown in FIG. 4, the female connector further includes a lever 10 for facilitating fitting; a CPA (connector position assurance) 11 for fixing the lever 10 in position after the completion of the fitting; a sealing ring 12 for providing waterproofing between the male and female connectors; a wire seal 13 for providing waterproofing between the cable 16 and the outer housing 4; and a tail plate 14 for holding the wire seal 13.
The cable 16 is provided with a braided shield, and an outer ferrule 30 is swaged onto the braided shield in order to provide electrical connection between the braided shield and the outer housing 4. FIG. 6 is a schematic illustration showing a perspective view of an outer ferrule of a conventional connector. As shown in FIG. 6, the outer ferrule 30 includes a cable-swaging portion 31 for swaging the outer ferrule 30 onto the braided shield of the cable 16 and a spring portion 32 for providing contact to the outer housing 4.
When the connector is mounted in a place subject to vibration (such as in a vehicle), the cable 16 connected to the connector will suffer from vibration. In such a case, the vibration propagates to the female terminal 6 of the female connector connected to the cable 16, causing friction at the contact between the male terminal 3 and the female terminal 6. This will cause undesirable effects such as abrasion of the contact surface platings, thus increasing the contact resistance between the male terminal 3 and the female terminal 6.
FIG. 7 is a schematic illustration showing a longitudinal-sectional view of the FIG. 6 outer ferrule. More specifically, in the conventional connector shown in FIG. 7, the cable 16 contacts the female outer housing 4 of the connector via several bumps 33 spaced along an outer perimeter of the spring portion 32 of the outer ferrule 30. This configuration has, in the circumferential direction, multiple contact points between the spring portion 32 and the outer housing 4, but it has only one contact point in the longitudinal direction. Therefore, as shown by the broken line of FIG. 7, the cable 16 can swing about one of the contact points between the spring portion 32 and the outer housing 4 (i.e., the contact point functions as the pivot point of the swing), thus causing a vibration of the cable 16 to propagate to the female terminal 6. Such a vibration will in turn increase the contact resistance between the male terminal 3 and the female terminal 6.
To solve this problem, JP-A-2007-103087 discloses a connector which can prevent any vibration of a cable from directly propagating to its terminal.